Methods and means for facilitating removal of offshore platform supports from mud



Dec. 18, 1956 J; T. HAZAK 7 8 METHODS AND MEANS FOR FACILITATING REMOVAL OF OFFSHORE PLATFORM SUPPORTS FROM MUD Filed Nov. 18, 1955 4 Sheets-Sheet 2 INVENTOR. Jo'H/v TIE 2124K I BY ATTORNEY.

Dec. 18, 1956 Filed Nov. 18, 1955 J. 'r. HAZAK 2,774,218 METHODS AND MEANS FOR FACILITATING REMOVAL OF OFFSHORE PLATFORM SUPPDRTS-FROM MUD 4 Sheets-Sheet} IN VEN TOR.

JOHN THAZAK mmmmdz ww ATTOENEKF.

Dec. 18, 1956 2,774,218

. J. T. HAZAK METHODS AND :MEANS FOR FACILITATINGREMOVAL 0F OFFSHORE PLATFORM SUPPORTS FROM MUD INVENTOR. L/H/V Z'h'hzA K.

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United States PatentO "ice NIETHODS AND MEANS FOR FACILITATING RE- MOVAL OF OFFSHORE PLATFORM SUPPORTS FROM MUD John T. Hazak, New York, N. Y., assignor to Raymond Concrete Pile Company, New York, N. Y., a corporation of New Jersey Application November 71s 1955, Serial No. 547,809 13 Claims. 01. til-46.5)

This invention relates to mobile marine platforms of the type which are especially useful in'oifshore boring and drilling operations and, more particularly, to means and methods for facilitating removal of the supporting members of such platforms from the ocean floor when it is desired to move the platform from one offshore location to another.

Mobile marine platforms of the type which may be floated to the desired offshore location, securely anchored in operative position at such location for an indefinite length of time and then readily returned to a floating condition for transportation to another ofishore location are attaining widespread commercial usage. Such platforms, while of many varied designs, in general, comprise a deck structure which is carried at the desired height above the water surface by means of supporting members, for example, spuds or piles, which extend downwardly into contact with the sea floor-when the platform is in operative condition and are adapted to be raised but of contact therewith when it is desired to move the platform to a different location. Experience with heretofore known constructions has shown that such removal of the deck supported members out of contact with the sea bottom is oftentimes a diflicult and at best a very time-consuming task. For example, in some platforms the deck is supported by a plurality of piles which are jacked down so as to penetrate into the sea bottom, and in this type of construction removal of these members requires a reverse jacking operation which is most time consuming. Such a time delay when changing ofishore locations is, of course, an expensive item, and this is especially true when the platform is desired to be used to take exploratory borings at a large number of offshore locations, therefore requiring frequent change of position. In an effort to speed up this removal opera tion, enlargements have been provided at the base of the supporting members; for example, large area spud pads are secured to the lower. ends .of each spud member, thereby spreading the load carried by each spud over a relatively large area of sea bottom andhence preventing deep penetration of the same into the ocean floor. While such spud pads do succeed in preventing any substantial spud penetration, the pad itself will sink in varying degrees into thermud usually found on the sea floor, andthus a still serious problem of spud removal exists due to the great force of suction which, is: created between the under-surface .of each pad'and that. In another common type. of mobile platform' mud. having an anchor barge. connected to a plurality of supporting spuds or members, an equally great suctional force problem exists when it is attempted to raise the barge from the sea floor.

Various means and methods have heretofore been utilized in an attempt to break this suctional force. Thus hinged spud pads have been provided, mounted eccentrically of their spud, so that 'by pulling upwarden the pad, the same will tend to tilt and thus perrnitjair to 2,774,218 Patented Dec. 18,1956

enter at one edge and breakthe suction. Aside from inevitable operational difiiculties of this type of device, the hinged construction thereof is costly and may. be troublesome. It has also been proposed to break the suction by putting pipes down through the spud. pads.

or anchor barge and then forcing fluid under pressure to the underside of these'members in an attempt to equalize pressures above and below the same. Such} pipes have proven unsuccessful because of the well known tendency of any such' fluid under pressure to' seek and es cape by the path of least resistance. Thus, when fluid is forced through such pipes, instead of spreading out -uni-.

*formly over the entire underside of the spud pad or barge, which would benecessary to equalize pressures .as

aforesaid, the same in actual practice will form a narrow channel or hole only in those portions where the mud, is most loosely packed and, following that channel, will escape from beneath the member.

The instant invention overcomes these advantages .of

the prior art arrangement by providing over the bottom and preferably also the sides of the supporting member end enlargement, such as a spud pad or barge, a flexible covering which by design is impermeable to both mud and water in combination with means to introduce fluid under pressure substantially uniformly over the space between said cover and the underside of said pad or barge, thereby equalizing pressures above and below the pad or barge and breaking the suction force therebetween when it is desired to lift the pad or barge from the sea floor.

According to the method of the invention, such a flexible, mud and water impermeable cover is secured in place over the bottom and sides of the enlarged end 'porit is desired to lift the supporting'member, fluid under pressure isintroduced into the space between the underside of said enlarged portion and its cover, thereby equalizing pressures above and below said portion. The supporting member can then be raised, leaving the support end cover in place on the sea floor, and the cover then retrieved so as to permit re-use of the same.

According to one embodiment of the invention, this support end cover'may comprise a sheet of flexible material having an impermeable outer layer designed to prevent passage of water or mud therethrough and a permeable inner layer designed to permit passageof fluid under pressure from the upper to the lower surface of. the enlarged end portion of the supporting member.

According to another embodiment of'the invention,

" the covering may comprise simply a layer of impermeable flexible material andinthis embodiment conduit means, extending down to the undersurface of the enlarged end portion of the supporting member, provide ;meansyfor introducing fluid underpressure to the space between said undersurface and covering.

tion hereof will appear from theldetaile'ddescription given below-taken in connection with the'accompanying draw-z, ings which form a part of. this specification and illustrate by way of examplepreferred embodimentsof the invenr;

an- ,In thedrawings:

Fig.1 is an elevationalseetionishowing one embodiment of the support end cover of the invention s'ecuredin position on the spud pads of a mobile marine platform;

Fig. ,2 is a vertical sectional view showing manually operable means for retrieving the support end cover from the ocean floor after lifting of its supporting member;

Fig. 2a is a fragmentary elevational view showing an alternative embodiment of the support end cover of the invention secured in position on a spud pad.

Fig. 3 is an elevational view showing a support end cover similar to the embodiment shown in Fig. 2 but having supplemental pressure equalizing means secured in position on an anchor barge of a mobile marine platform; I Fig. 4 is an enlarged fragmentary elevational view partly in section of a support end cover according to the invention secured to a spud pad and having automatic means for retrieving said cover after lifting of the spud P Fig. 5 is an enlarged fragmentary sectional showing of a portion of the apparatus of Fig. 4;

Fig. 6 is a schematic view of the apparatus of Fig. 4 showing the relation of the support end cover to its spud pad upon lowering of said spud pad into position on the ocean floor;

I Fig. 7 is a schematic view similar to Fig. 6 but showing the relative positioning of the support end cover to its spud pad just prior to removal of the latter; and

Fig. 8 is a schematic view similar to Fig. 7, but showing the relation of spud pad and end cover after the pad has begun its travel to the surface of the water.

Referring now in more detail to the drawings and particularly to Fig. 1 thereof, support end covers 20 according to one embodiment of the invention are there shown secured in operative position covering the bottom and sides of spud pads 21. These spud pads 21 are secured to' the lower end of spuds or piles 22 which support the working deck 23 of a mobile marine platform. This mobile marine platform may, for example, be of the type of fibrous material, for example, fiber glass for woven hemp or sisal fibers. As shown in Fig. 1 the upper extremities of this inner layer preferably extend above the upper surface of the spud pad 21 as at 29 and are therefore in constant communication with the water above the spud pad. Handling line's 30, 31 are suitably secured at oneend, to thesupport end cover 28 as at 32 and at their other ends to the platform deck 23.

When it is desired to move the platform to another offshore location, supporting spuds 22 may readily be raised from their position on the bottom shown in Fig. l as fol lows. After the de'c l 23 has been'lowered to the surface f the water as described in the copending application mentioned above, jacking means 24 can be energized to disclosed in a copending Edward A. Smith application 7 Serial No. 378,460; filed September 4, 1951, and may be provided with jacking means at 24 mounted on the deck and designed for jacking the supporting spuds with their enlarged pads up or down relative to the deck 23, and

vice versa. The operation of this type platform will be substantially the same as that described in said copending application except that herein enlarged spud pads 21 have been secured to the lower ends of the spuds 22 in order to prevent deep penetration of those spuds into the mud. These spud pads may, for example, consist of hollow, rectangular, reinforced metal tank-like elements which are dimensioned so as to cover an area many times the crosssectional area of the spud to which they are attached, thereby spreading out the load carried by that spud over a much larger area of ocean floor and hence preventing deep penetration. Of course, a spud pad as shown in Fig. 1 will penetrate to a slight degree into the mud 25 found on the ocean floor and as a result, suction forces will be created which must be overcome before the spud can be readily raised from the bottom.

According to the invention hereof, the support end cover 20 is flexible and comprises an impermeable outer layer or skin 26 which is suitably joined to a permeable inner layer 27. The impermeable outer layer 26 might, for example comprise a piece of canvas impregnated with a rubber or synthetic resin coating or any suitable fabric impregnated with a plastic coating so as to render the same impervious to the passage of water or mud. The inner permeable layer 27 constitutes in this embodiment the means to introduce fluid under pressure substantially uniformly over the space between the underside 28 of the spud pad 21 and the outer layer or skin 26 of the end cover. This inner layer 27. is designed was to provide a plurality of small or minute passages extending through out its dimensions which are capable of permitting the passage of water. Preferably, this layer may be formed lift the spud 22 from the bottom. Because of the presence of the end cover 20, no substantial suctional force will be encountered in opposition to the raising of this spud and its pad, for, as mentioned previously, the upper extrernities of the covers inner layer are constantly exposed to the water above padZl, and therefore water under pressure will enter the pores or interstices between the fibers of this permeable member 27 and will travel downwardly and spread uniformly throughout the entire extent of said inner layer. Thus water under the same pressure which is prevalent at thetop side of the spud pad 21 will be introduced substantially uniformly over the entire underside of this spud pad, thereby equalizing pressures above and below this member and thus eliminating the suction forces. In order to supplement this introduction of fluid under pressure to the underside of the spud pad 21, hollow pipes or conduits such as 33 may be provided extending from the top to the bottom of the pad, thereby insuring an ample flow of water to the lower portions of the permeable layer 27.

After the spud 22 and its pad have been lifted a suitable distance from the sea floor, the support end cover 26 may be retrieved by pulling upwardly upon lines such as 30 in the following manner. It will be, of course, evident that after removal of spud pad 21 a suction force ,will still exist between the underside of the covers outer skin 26 and the mud, which force will preclude removal of the. cover by pulling directly upwardly of lines 30 and 31. However, as shown in Fig. l, a guide line 34 secured atone endto the platform deck as at 35 and extending ,und er said platform and transversely thereof to a connection with the upper end of line 30 at 36 may be provided, then when it is desired to retrieve the end cover 20, by slacking off on the connection of line 36 to the platform deck and taking up on guide line 34, the line 30 may be moved to the angular position shown in Fig. 2 and when in this position by pulling thereon, the cover 20 may be gradually peeled from its engagementwithtliemud as shown at 37, thereby breaking thes'uctiori force gradually and permitting ultimate rctrieyingof thecover by raisingthe lines 30 and 31.

Turning'now to Figure 2a, an alternative embodiment ofthe'invention is there disclosed which comprises a support end cover 40, the same being formed of a layer ors kin of water impermeable material such as rubber coated canvas or plastic impregnated cloth. This cover 40-issecured in operative position coven'ng the bottom and sides of a spud pad 41 which is provided at the lowerlend of a spud 42, in the same manner as described in connection withtheernbodiment in Fig. 1. Similarly,

handling lines 43 and 44 may be provided to retrieve the cover However, in this embodiment in place ofla permeable inner layer such as 27,jsupra, the means for introducing fluid under pressure to the underside of the spud pad 41 comprises one or more open ended tubes or pipes 45 which extend from the upper to the lower surface of the spudpad and whose upper ends are connected toflexible' tubes or conduits 46 with the latter being connected to a source of fluid such as air or water under pressure. In this embodiment when it is desired to remove the spud and spud pad, the operation is identi cal with thatdescribed in the embodiment in Fig. 1 except that just prior to such removal air or water under pressure is injected via lines 46 and conduits to the underside of the spud pad 41. Because of the presence of the impermeable skin or cover 40 surrounding the undersurface of the spud pad, this fluid under pressure will not be permitted to escape along the path of .least resistance as described above in connection with the prior art and hence will spread substantially uniformly over the entire undersurface of said spud pad, thereby equalizing pressure above and below the same and breaking the suctional forces.

In Fig. 3 there is shown a support end cover 50 secured in operative position to cover the bottom and sides of an anchor barge 51. Secured to this anchor barge 51 are a plurality'of vertically extending supporting members such as piles or spuds 52 which carry at their upper ends the deck 53 of a mobile marine platform. Such an anchor barge type mobile platform may if desired be constructed, to operate in accordance with the principles described in the copending application of John T. Hazak, Serial No. 449,998 filed August 16, 1954. Thus, initially, the barge is in the buoyant condition along with its deck 53 and supporting members 52 can be floated to the desired offshore location at which time barge 51, with its end cover 54) in position, is sunk to the ocean floor as shown in Fig. 3. When it is desired to remove such platform to a different location, the same suction force problem opposes lifting of this barge 51 as was the case in the spud pad designof Fig. 1. However, because of the inherent larger size of such an anchor barge the suctional force encountered is even greater. The end cover 50 as stated above may be identical in design to the cover 20 described in connection with Fig. 1, and comprise an impermeable outer layer or skin 54 and a permeable fibrous inner layer 55. Once again the upper extremities of this inner layer 55 are in continuous communication with the water above barge 51 as shown at 56, thereby permitting passage of this water under pressure throughout the entire area of the fibrous layer 55 and hence equalizing pressure above and below the anchor barge. Once again, if desired, supplemental means for introducing fluid under pressure onto the underside of this anchor barge and thus to the fibrous layer 55 may be provided; for example, a plurality of open-ended pipes 57,- extending from the top to the bottom of the anchor barge, may be connected via hose or conduits 58 to a common leader 59 located on the platform deck 53. Then fluid such as air or water under pressure may be forced by a pump 60 through leader 59, conduits 58, and pipes 57 to the underside of the anchor barge, thereby insuring a substantially uniform spread of pressure fluid throughout the area of the underside of the barge. In this connection, it should be understood that in place of the pressure system 58, 59 and 60, the. pipes 57 might simply be left open at their upper ends to the sea water as are pipes in Fig. 1-. It should be further understood that a support end cover, comprising merely an impervious skin such as 40 in Fig. 2a could be employed with similar success on an anchorbarge such as 51. Handling lines 61 may again be provided attached to the end cover 50 for retrieving the same after raising of the anchor barge.

Turning now to Figs. 48, means for retrieving the support end cover of the invention automatically with the removal of the supporting member are there illustrated. An end cover according to the invention is there shown secured in operative position covering the bottom and sides of a spud pad 71. This cover 70 as shown is similar in make-up to the cover described in connection with Figs. 1 and 3 and comprises an impermeable outer layer 72 and a permeable inner layer 73. Referring for the moment to Fig. 5, the preferred construction of such a permeable inner layer 73 is there shown and as will'be seen, it takes the form of a woven fibrous mat composed ofa tion, it will be noticed, provides a pluralityvof small, voids orinterstices 76 which extend throughout the.entire area of the permeable inner layer, thereby permitting the-flow of fluid under pressure therethrough. Again the upper extremities of this fibrous inner layer are ex posed as at 77 to the water. located above spudpad 7'1. Thuswater under pressure willflow through the voids or interstices 76 of the permeable inner layer and spread over the entire 'unde rsurface of spud'pad 71. v

In order to providefor automatic retrieving of the support end cover.70, the upper extremities of said cover are secured by means of suitable clamps 80 and lines'8l to the upper surface of the spud pad 71. The cover itself is dimensioned so as to be large enough to permita plurality of inflatable rings or tubes 82 to be inserted between the said cover and the sides of the spud pad. These rings or tubes are positioned so as to surround'th'e sides of said spudpad and may beformed 'o'f'any mate-. rial'which, though flexible, will not stretch substantially circumferentially in cross-section upon being subje'ctedto internal fluid pressure. For-inflating these tubes'8 2, con duit means 83 are provided extending downwardly from a source of pneumatic fluid under pressure on the deck of the platform and passing internally of. the spud pad 71 to a leader 84 which connects through a lines 85 with the interiors of said tubes.

Turning to Figs. 6-8, the operation of this automatic coverretrieving means will be understood; As shown in Fig. 6, the spud pad 71 with its cover 70 clamped in operative position thereon is lowered to the ocean floor. As shown, the tubes or rings 82 are in the collapsed condition during this positioning of the pad. Then when it is desired to remove the pad, the rings 82 ar'first inflated as shown in Fig. 7, thereby forcing the mud laterally away from the sides of the spud pad as shown at 87, 88. The

plurality of branch spud pad is'then lifted from the sea floor in conventional i manner. It will be obvious that because fluid under pressure has been introduced to the underside of this pad via permeable layer 73, as'described above, there will be no suctional force existing between the same and the cover 70.. Therefore, the spud pad canbe raised to the position above the sea bottom as shown. in Fig. 8. When this lift-' ing of spud pad 71 commences, although the bottom of cover 70 will still be held by suction on the sea floor, its upper extremities beingsecu'red to the said pad by the clamps 80, an upward pull will be exerted thereon, which pull will tend to flatten the flexible inflatable tubes 82, thereby causing the cover 70 to graduallypeel away from the' mud as shown at 899 0. Once again this peeling action will gradually break the suctional forces involved and the coverwill eventually be'carried to the surface with the spud pad. 'It should be, of course, understood that while in connection with this automatic cover retrieving means the cover has been shown similar in con struction to the embodiment in 'Figs.'1 and 3,'sup'ra, a 1

cover constructed according to' the embodiment of Fig. 201 could be employed. Furthermore, it should be under: stood that this automatic cover retrieving means could be employed with equaffacility on an anchor barge such as 51 (Fig. 3). r

Although certain particular embodiments of the inven: tion are herein disclosedfor purposes of explanation, various further modifications thereof, after study of this'specification, will be apparent to those skilled in the artlto which the invention pertains. Reference should accordingly be had to the appended claims in determining the scope of the invention. What is claimed and desired to be secured by Letters Patent is: j 1. Apparatus for facilitating removal of the bottom end portion of a supporting member of a marine platform from contact with the mud onsthe ocean floor whic h plurality of intertwiningfibers. 74, 75.. As mentioned. above, these could be either glass fiber or sisal or hemp fibers or the like. Sucha construccomprisesa support end: cover formed of flexible, water ermeable material adapted to receive such end portion of said supporting'member, in combination withmeans to' introduce fluid under pressure substantially uniformly over the space between said end portion and said cover, thereby substantially eliminating any suction forces existing therebetween when such end portionl'is being raised from the'r'nud.

t2. Apparatus for facilitating removal of the bottom end portion of a supporting member of a marine platform from contact with the mud on. theocean floor, which comprises a support end cover formed of flexible, water impermeable material adapted to' receivesuch end portion of said supporting member, in combination with means to introduce fluid under pressure substantially uniformly over the space between said end portion and said cover, thereby substantially eliminating any suction forces existing therebet'we u when such end portion is being raised from the mud, sai d means comprising a layer of water permeable material secured to said impermeable cover and adapted tobe positioned between the latter and the supporting m -5.. y

r 3; Apparatus for facilitating removal of the bottomend portion of a supporting member of a'marine platform from contact with the mud on the ocean floor, which comprises a support end cover formed of flexible, water impermeable material adapted to receive such end portion of said supporting member, in combination with means to introduce fluid under pressure substantially uniformly over the space between said end portion and said cover, thereby substantially eliminating any suction forces existing therebetween when such end portion is being raised from, the mud, said means comprising conduit means extendingthroughthe end portion of said supporting member and adapted to deliver fluid under pressure to the underside thereof. a

a 4. Apparatus for facilitating removal of the bottom end portion of a supporting member of a marine platform from contact with the mud on the ocean floor, which comprises a support end cover adapted to receive such end portion of said supporting member, saidcover comprising an outer layer of water impermeable material and an inner layer of water permeable material, the extremities of said inner layer extending above said end portion so as to be in contact with the water thereabove.

v 5, Apparatus for facilitating removal of the bottom end portion of a supporting member of a marine platform from contact with the mud on the ocean floor, which comprises a support end cover adapted toreceive such end portion of said supporting member, said cover comprising an outer layer of water impermeable material and an inner layer of water permeable material, the extremities of saidinner layer extending above said end portion so as to be in contact with the 'water thereabove, and supplemental fluid pressure introducing conduit means extending to the underside of the end portion of said supporting member. I y 7, a

,6 Apparatus for effecting ready removal' of the enlarged end portion of a supporting member of a marine platform fromfcon'tact withthe mudon the ocean floor, which comprises a water impermeable support end cover adapted to receive such enlarged endportion of said supporting member in combination with fluid pressure delivering conduit means extending through said enlarged endfpofrtion andgadapte d to introduce fluid under pressure to the space betweensaid end portion and said cover. fl fApparstus ffor eifcct'ingready removal of the enlarged end portion of a supporting member of a'marine platform from contact with the ocean floor whieh comprises ,a support end cover adapted to receive said enlarged end portion and having a flexible water impermeable outer layer and a flexible water permeable fibrous,

innerlayer having numerous small passageways extending ther'ethrough adapted toperr'nit the distribution there- 7 through of fluid under pressure.

. adapted to receive such end portion of said supporting member, in combination with means to distribute fluid under pressure over the space between said end portion and said cover, thereby substantially eliminating any suction forces existing therebetween when such end portion is being raised from the mud, and handling line means secured at one end to said cover and adapted to be secured at the other end to said platform, whereby said cover may be retrieved from the ocean floor after the supporting member has been removed therefrom.

V 9. Apparatus for facilitating removal of the bottom end portion of a marine platform support from contact with the mud on the ocean floor which comprises a support end cover formed of flexible water impermeable material adapted to receive the end portion of said support and secured thereto, in combination with means to distribute fluid under pressure substantially uniformly over the space between said end portion and said cover, thereby substantially eliminating any suction forces existing therebetween when such end portion is being raised from the mud, and inflatable tube means positioned between said cover and the sides of said end portion adapted to provide for automatic retrieval of said cover as the supporting member is removed from the ocean floor.

10. A method of facilitating removal from the sea floor of the enlarged end portion of a supporting member of a marine platform which comprises securing a water impermeable cover around the bottom and sides of said enlarged end portion, introducing fluid under pressure to the space between said enlarged portion and its cover, thereby reducing the suction forces existing therebetween when such end portion is being raised from the mud, and raising said enlarged end portion from the sea floor while leaving the cover in place on the sea floor and then retrieving said cover. I

11. A method of facilitating removal from the sea floor of the bottom end portion of a supporting member of a marine platform which comprises securing a water impermeable cover around the bottom and sides of said end portion, said cover having handling lines secured thereto, introducing fluid under pressure to the space between said end portion and its cover, thereby reducing any suction forces existing therebetween when such end portion is being raised from the mud, and raising said end portion from the sea floor while leaving the coverin place on the sea floor and then retrieving said cover by raising said handline lines.

12. A method of facilitating removal from the sea floor of the bottom end portion of a. supporting member of a marine platform which comprises securing a water impermeable cover around the bottom and sides of said end portion, positioning inflatable tube means between said cover and the sides of said end portion, introducing fluid under pressure to the space between said end portion and said cover, inflating said tube means, and then raising said end portion from the sea floor, thereby automatically retrieving said cover from the sea floor.

13. A method of effecting ready removal of the bot- 7 tom end portion of a marine platform supporting member from the sea floor which comprises positioning a water impermeable cover around the sides and bottom of said end portion prior to lowering said end portion to the sea floor, then lowering said end portion to the sea floor, introducing fluid under pressure between the underside of said end portion and said cover, thereby substantially equalizing pressures above and below said portion, raising said end portion from the sea floor and then retrieving said cover from the sea floor.

No references cited. 

